When bitumen or heavy oil is extracted from tar sands it is not initially in condition for further processing into usable petroleum products. Usually the bitumen is processed in a reactor or a coker, in which atomized droplets of the bitumen in a carrier such as steam are heated to produce low-boiling petroleum products. The efficiency of the coking process is enhanced if the bitumen droplets are of a uniform small diameter, of the order of 300 μm. In a typical installation the bitumen is introduced into a flowing stream of high pressure steam and preferably is broken down into bubbles or particles as the 2-phase mixture of bitumen and steam flows along a mixing apparatus which then pass through an atomizing nozzle into the interior of the reactor or coker for further processing therein.
One installation for achieving atomized bitumen in steam is found in U.S. Pat. No. 6,003,789. It uses a mixing assembly or apparatus as is illustrated in FIG. 1 therein, wherein an atomizing nozzle 20 is mounted in the wall of the reactor, a cylindrical conduit 24 is attached to the nozzle and a pair of parallel conduits 25 and 26 are provided for introducing steam and bitumen respectively into the main conduit 24, conduit 26 being downstream of conduit 25. It will be noted that the conduits 25 and 26 meet the conduit 24 generally at right angles with respect thereto. A flow-accelerating nozzle 22 is provided in the conduit 24 between the junctures of the steam and bitumen conduits 25 and 26 with the conduit 24. The nozzle 22 is intended to increase the flow velocity of the steam to improve break-up of the bitumen into bubbles or droplets. A valve is shown at the end of the conduit 24 opposite the atomizing nozzle 20 and upstream of the steam conduit 25, for use in introducing a cleaning rod into the conduit 24. The rod is used to clear blockages within the conduit 24 and the atomizing nozzle 20. It will be apparent that the minimum orifice size of the nozzle 22 cannot be less than the diameter of the cleaning rod, since the nozzle 22 is located within the main conduit 24. Otherwise, the cleaning rod could not pass along the full length of the main conduit. This places a limitation on the efficiency of the entire apparatus.
The above installation is an improvement over previous installations but it is not without its faults, occasioned primarily by the manner in which the conduits 24, 25 and 26 are arranged relative to each other. There are problems with flows because of the 90° relation between the conduit 24 and each of the conduits 25 and 26. Furthermore, there are problems in arranging the conduits in and around the reactor due to the relative positioning of the various conduits.